This year’s presidential election inverts the foreign policy attributes of the 2008 candidates: Barack Obama is now tough and experienced, Mitt Romney fallow and untested.

One of John McCain’s more memorable assertions in 2008 was that he would "follow Osama Bin Laden to the gates of hell." Obama’s actions have spoken louder than McCain’s hyperbole. When the president sanctioned the raid that killed Bin Laden in Pakistan on 2 May 2011 – declining to inform Pakistan of US intentions and using ground forces instead of launching an airstrike – he largely armoured himself to Republican attacks on his lack of fortitude. So where can Romney land meaningful blows now?

Romney’s main problem is that he is running against an incumbent who – through a step-change in the frequency, audacity and lethality of drone attacks – has arguably waged war on Al Qaeda more effectively than his predecessor, and unarguably at a lower human and financial cost. (Predator strikes, while ethically problematic, kill fewer people than ground wars.) In this context how does Romney communicate a greater desire to confront America’s enemies without sounding like Barry Goldwater in 1964, whose belligerence was an electoral godsend to Lyndon Johnson?

Romney is rarely less convincing than when seeking to out-hawk Obama on facing down Iran, Russia – "without question our number one geopolitical foe" – and China. Perhaps it is self-awareness that explains his discomfort in espousing such views. For Romney’s operating principles closely resemble Obama’s. Indeed, during his acceptance speech at the Republican National Convention in Tampa, Romney failed to name a single substantive difference with Obama on foreign policy.

Romney won the governorship of Massachusetts because he knows where to find the centre, and he sought out the median voter through this year’s fractious Republican primaries. The Tea Party ensured that this point was farther to the right than at any time in his party’s history. But the key point is that Romney is hardwired to operate in the middle-ground of whatever constituency he is charged with persuading. And the world looks more like pluralist Massachusetts than it does a bloc of Republican primary voters.

As a serious candidate in the 2007 primaries, Romney was commissioned to write a thought-piece for Foreign Affairs. The purpose of the article was to mollify and reassure in a polarized political environment. In it he stakes out little new ground, instead identifying points of agreement among so-called realists and neoconservatives.

Romney observes that the United States is in need of ‘an overarching strategy that can unite the United States and its allies,’ but cautions that this should be formed "not around a particular political camp or foreign policy school but around a shared understanding of how to meet a new generation of challenges. Romney’s emphasis is on achieving results not on pursuing agendas.

His speech at the Citadel last October was his most important foreign policy speech to date. Its purpose was to characterise Barack Obama as defeatist and out of tune with American values – in the same way that Senator Henry ‘Scoop’ Jackson and Ronald Reagan lambasted Henry Kissinger through the 1970s. So Romney accused Obama of issuing an "eloquently justified surrender of world leadership," a depiction far removed from reality. The president is utterly devoted to ushering in another "American century," as his well-documented admiration for Robert Kagan – author of The World America Made, and a key adviser to Romney – amply illustrates.

There are, of course, clear differences in each person’s style. Romney consciously emulates Ronald Reagan’s optimism and moral certainties. But like Reagan in his second term, Romney is likely to talk and act in substantively different ways. Rich Williamson, a veteran GOP foreign policy adviser, has struggled to differentiate his man from Obama. Williamson identifies "fundamental differences about a naive faith in engagement and a dangerous reliance on the Security Council versus having an approach where you have strength, where you're willing to lead, and where you have strong relationships with our friends and allies." But who could honestly say that Obama is not willing to lead or have strong relationships with friends and allies? And would Romney really ignore the UN when it might serve a useful function? Obama and Romney are cut from the same cloth; a source of angst to the base of both parties.

Writing inthe Weekly Standard earlier this year, William Kristol observed that "Mitt Romney is an intelligent, hardworking, pragmatic problem-solver with a conservative disposition. He might as well present himself that way." This is true, though it fails to acknowledge the fact that Romney’s primary virtues – his competence, diligence and "small c" diplomatic conservatism – are also Obama’s.

A chasm separates the candidates on domestic policy and Congress is an alarmingly polarised and ineffectual place. On foreign policy, however, Obama and Romney share a method and a worldview. As an "etch-a-sketch" – as adviser Eric Fehrnstrom ill advisedly described him – Romney has shown a willingness to say and erase whatever it takes to win. But he will surely pursue a modest diplomatic agenda if a stagnant economy allows him to defeat Obama on election day. Authoring foreign policy with a permanent marker tends to concentrate the mind.

David Milne, senior lecturer in political history at the University of East Anglia, is the author of America’s Rasputin: Walt Rostow and the Vietnam War. A longer version of this article appears in the Chatham House journal, International Affairs.